Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters
SeaWiFS surface chlorophyll estimates and Levitus nitrate estimates in the Southern Ocean south of Australia (140E) show that this region is characterised by a high-nitrate low-chlorophyll (HNLC) regime typical of Southern Ocean waters. The HNLC conditions become more prominent moving south from the...
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Online Access: | https://doi.org/10.1016/j.jmarsys.2013.04.011 http://ecite.utas.edu.au/119059 |
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ftunivtasecite:oai:ecite.utas.edu.au:119059 2023-05-15T13:49:03+02:00 Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters Kidston, M Matear, R Baird, ME 2013 https://doi.org/10.1016/j.jmarsys.2013.04.011 http://ecite.utas.edu.au/119059 en eng Elsevier Science Bv http://dx.doi.org/10.1016/j.jmarsys.2013.04.011 Kidston, M and Matear, R and Baird, ME, Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters, Journal of Marine Systems, 128 pp. 123-137. ISSN 0924-7963 (2013) [Refereed Article] http://ecite.utas.edu.au/119059 Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Refereed Article PeerReviewed 2013 ftunivtasecite https://doi.org/10.1016/j.jmarsys.2013.04.011 2019-12-13T22:18:16Z SeaWiFS surface chlorophyll estimates and Levitus nitrate estimates in the Southern Ocean south of Australia (140E) show that this region is characterised by a high-nitrate low-chlorophyll (HNLC) regime typical of Southern Ocean waters. The HNLC conditions become more prominent moving south from the Sub-Antarctic Zone, with surface chlorophyll generally decreasing and nitrate increasing with latitude. Parameter optimisation experiments were performed using simulated annealing to fit a zero-dimensional nitrogen-based four-component ecosystem model to SeaWiFS surface chlorophyll data in the Sub-Antarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ). We hypothesise that bioavailability of iron limits phytoplankton growth in this region. A physiological indicator of iron availability was investigated by optimising three of the model parameters defining maximum photosynthetic growth and maximum photosynthetic efficiency of phytoplankton. The effect of zooplankton grazing and light, mixed layer depth and temperature forcing data on the optimisation results was investigated in further optimisation experiments. An error analysis of the optimised parameter estimates was performed by analysing the Hessian matrix of the cost function. The parameter optimisations indicate that phytoplankton growth rates in the Polar Frontal Zone and Antarctic Zone are limited by some process not explicitly included in this model, with iron availability being the most likely candidate. Based on these optimisations we support the theory that micronutrient availability is the primary cause of the HNLC conditions in the Australian sector of the Southern Ocean. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean eCite UTAS (University of Tasmania) Antarctic Southern Ocean Journal of Marine Systems 128 123 137 |
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Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
spellingShingle |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Kidston, M Matear, R Baird, ME Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
topic_facet |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
description |
SeaWiFS surface chlorophyll estimates and Levitus nitrate estimates in the Southern Ocean south of Australia (140E) show that this region is characterised by a high-nitrate low-chlorophyll (HNLC) regime typical of Southern Ocean waters. The HNLC conditions become more prominent moving south from the Sub-Antarctic Zone, with surface chlorophyll generally decreasing and nitrate increasing with latitude. Parameter optimisation experiments were performed using simulated annealing to fit a zero-dimensional nitrogen-based four-component ecosystem model to SeaWiFS surface chlorophyll data in the Sub-Antarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ). We hypothesise that bioavailability of iron limits phytoplankton growth in this region. A physiological indicator of iron availability was investigated by optimising three of the model parameters defining maximum photosynthetic growth and maximum photosynthetic efficiency of phytoplankton. The effect of zooplankton grazing and light, mixed layer depth and temperature forcing data on the optimisation results was investigated in further optimisation experiments. An error analysis of the optimised parameter estimates was performed by analysing the Hessian matrix of the cost function. The parameter optimisations indicate that phytoplankton growth rates in the Polar Frontal Zone and Antarctic Zone are limited by some process not explicitly included in this model, with iron availability being the most likely candidate. Based on these optimisations we support the theory that micronutrient availability is the primary cause of the HNLC conditions in the Australian sector of the Southern Ocean. |
format |
Article in Journal/Newspaper |
author |
Kidston, M Matear, R Baird, ME |
author_facet |
Kidston, M Matear, R Baird, ME |
author_sort |
Kidston, M |
title |
Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
title_short |
Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
title_full |
Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
title_fullStr |
Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
title_full_unstemmed |
Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters |
title_sort |
phytoplankton growth in the australian sector of the southern ocean, examined by optimising ecosystem model parameters |
publisher |
Elsevier Science Bv |
publishDate |
2013 |
url |
https://doi.org/10.1016/j.jmarsys.2013.04.011 http://ecite.utas.edu.au/119059 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
http://dx.doi.org/10.1016/j.jmarsys.2013.04.011 Kidston, M and Matear, R and Baird, ME, Phytoplankton growth in the Australian sector of the Southern Ocean, examined by optimising ecosystem model parameters, Journal of Marine Systems, 128 pp. 123-137. ISSN 0924-7963 (2013) [Refereed Article] http://ecite.utas.edu.au/119059 |
op_doi |
https://doi.org/10.1016/j.jmarsys.2013.04.011 |
container_title |
Journal of Marine Systems |
container_volume |
128 |
container_start_page |
123 |
op_container_end_page |
137 |
_version_ |
1766250716168454144 |